input_ff_create — create force-feedback device
| int input_ff_create ( | struct input_dev * dev, | 
| unsigned int max_effects ); | 
devinput device supporting force-feedback
max_effectsmaximum number of effects supported by the device
   This function allocates all necessary memory for a force feedback
   portion of an input device and installs all default handlers.
   dev->ffbit should be already set up before calling this function.
   Once ff device is created you need to setup its upload, erase,
   playback and other handlers before registering input device